Hi Kim,

  The serum tryptase test accurately reflects the tryptase level in the blood at the time the sample is taken, and it's an indicator of whether an anaphylactic or anaphylactoid reaction is taking place or has taken place recently.  Depending on the timing, it might not reflect what is happening in the patient's body.  Someone can have a mast cell activation problem and have normal tryptase.  I hope this excerpt from a lab website answers your question.  If not, post a more specific question, and I'll try to answer....:

"Tryptase

The measurement of serum levels of mast-cell specific products can clarify the diagnosis of anaphylaxis in ambiguous circumstances (e.g. defining vasovagal responses versus anaphylaxis, or defining cause for hypotension intraoperatively). Histamine elevation is transient (peak missed if collected beyond one hour) with false-positives occurring through basophil activation in clotted tubes. For this reason tryptase is the preferred marker for demonstrating mast-cell degranulation.

Levels of serum tryptase, a mast–cell specific protease, peak at one hour after an anaphylactic/ anaphalactoid reaction and remain elevated for approximately six hours, making tryptase a useful test for most emergency situations. Ideally, serum tryptase levels should be collected between one and six hours following an anaphylactic episode. Elevated serum tryptase implies either massive mast cell degranulation (as in anaphylaxis) or a condition with too many mast cells (e.g. mastocytosis). It should be remembered that not all cases of true anaphylaxis are accompanied by tryptase elevation. For example, some cases of food-induced anaphylaxis display normal tryptase levels, perhaps through basophil-mediated histamine release. Nevertheless, tryptase elevation has been quoted as possessing 95% sensitivity and 95% specificity for clinically significant mast-cell-mediated anaphylactic/anaphalactoid events, which offers a positive likelihood score of 19 (making anaphylaxis 19-times more likely than before the test was done). "

Source:  [urlhttp://www.haps.nsw.gov.au/research/Communique_List/Tryptase_and_Anaphylaxis.aspx[/url]

There can be false positives as well...I don't know why but NIH thought my husbands was a false positive and only until they sent it to Dr Schwartz lab and he confirmed that it was tryptase coming from mast cells that they told us it wasn't. Of course I always thought it was accurate because my whole family has elevated tryptases and couldn't all be testing false/positive. My husbands tryptase level also never really changed it was always in the 25 range.

If you go into anaphylactic shock your tryptase level is always elevated, even in non masto people.

oops sorry thats what they told me at NIH, so does that mean that sometimes tryptase is released from something other than mast cells

wow do you know what test would determine if they are coming from basophils or how would you find out if your basophils would degranulate.

Thank you Heather! since were on the subject of basophils can we skip to eosinophils...

what if your eosinophils are elevated?

Im asking because my daughter labs came back from NIH and she had elevated eosinophils, tryptase 20, ANA 2.1, IgE 1950...